Cellulose nano-particles are produced from native cellulose, which is comprised of D-anhydro-glucopyranose units bonded through beta 1,4 glycosidic linkages. They are produced through a variety of processes and are generally described as having at least one dimension in the 1 to about 100 nm range (Charreau et al. 2013). Nanocellulose fiber (NCF) are derived through three main processes and have different characteristics based on the process used to isolate them. Isolation or extraction of nano-particles from native cellulose is commonly achieved through either 1) acid hydrolysis, creating cellulose nanocrystals (NCC) or whiskers; 2) through mechanical treatment creating, microfibrillated cellulose (MFC) or 3) production via bacteria synthesis, as described by Iguchi et al. (Iguchi et al. 2000).
A wide range of applications have been developed for NCF which take advantage of their high strength and stiffness, abundance, renewability, high aspect ratio and biodegradability (Charreau et al. 2013). The high reactivity of nanocellulose fiber is due to the high number of hydroxyl groups and hydrophilic character. Much effort has been put forward to modify the surface of NCF to make it compatible with various polymers from cellulose acetate (Holbek 1984) to hydrophobic polymer matrices (Bordeanu et al. 2010) so that the range of applications of the modified NCF can be expanded. Various techniques using organic solvents have been developed and involve reacting the hydroxyl groups with silanes, polyethylene glycol (PEG), and polypropylene (PP) (Bordeanu et al 2010). A greener approach of in-situ graft co-polymerization of hydrophobic vinyl acetate and methy methacrylate onto NCC in aqueous medium has been done, achieving some increase in the NCC hydrophobicity (Hamad and Su 2011). Post treatments of NCF have been developed to endow the fiber with hydrophobicity by acetylation, these include works by Rodionova et al. (Rodionova et al. 2010). Others have used sillation with chlorodimethyl isoprpylsinae (Cavaille et al. 2000).
It would be very advantageous to provide a process of surface modification of NCF which can be tuned to give a liquid solution containing modified NCF having various degrees of liquidphobicity and which can be stored for long periods of time in a stable state and can be transferred to secondary surfaces such as fiber, paper, wood, glass, etc, which can then be used to produce any number of products in a large variety of applications.